The figure shows a distance vs. time graph of an object with three distinct regions, I, II, and III.
The objects acceleration is negative in region III.
a.
True
b.
False
[Ques. 2] The force of static friction exerted on an automobile's tires by the ground
a. provides the accelerating force that makes the car move forward.
b. does positive work on the car while it is accelerating.
c. does negative work on the car while it is decelerating.
d. does everything listed in (a), (b) and (c).
e. only does positive or negative work as in (b) or (c).
[Ques. 3] Positive work can be done
a. by friction on the tires when a car is accelerating without skidding.
b. by a spring when it launches a clown in the air.
c. by a hand throwing a ball.
d. by all of the above.
e. only by (b) and (c) above.
[Ques. 4] The figure shows a distance vs. time graph of an object with three distinct regions, I, II, and III.
The objects acceleration is zero only in region II.
a.
True
b.
False
[Ques. 5] Negative work can be done
a. by friction on the tires while a car is accelerating without skidding.
b. by a spring at the bottom of an elevator shaft when it stops a falling elevator.
c. by a hand catching a ball.
d. by all of the above.
e. only by (b) and (c) above.
[Ques. 6] The figure shows a distance vs. time graph of an object with three distinct regions, I, II, and III.
The objects velocity is never negative.
a.
True
b.
False
[Ques. 7] Sally, who weighs 450 N, stands on a skate board while Roger pushes it forward 13.0 m at constant velocity on a level straight street. He applies a constant 100 N force.
a. The work Roger does on the skateboard is 0 J.
b. The work Roger does on the skateboard is 1 300 J.
c. The work Sally does on the skateboard is 1 300 J.
d. The work Sally does on the skateboard is 5 850 J.
e. The work Roger does on the skateboard is 5 850 J.
[Ques. 8] A 30-kg child sitting 5.0 m from the center of a merry-go-round has a constant speed of 5.0 m/s. While she remains seated in the same spot and travels in a circle, the work the seat performs on her in one complete rotation is
a. 0 J.
b. 150 J.
c. 1 500 J.
d. 4 700 J.
e. 46 000 J.
[Ques. 9] The figure shows a distance vs. time graph of an object with three distinct regions, I, II, and III.
The objects velocity is positive in region II.
a.
True
b.
False
[Ques. 10] Two eggs of equal mass are thrown at a blanket with equal velocity. Egg B hits the blanket but egg A hits the wall instead. Compare the work done on the eggs in reducing their velocities to zero.
a. More work was done on A than on B.
b. More work was done on B than on A.
c. The amount of work is the same for both.
d. It is meaningless to compare the amount of work because the forces were so different.
e. Work was done on B, but no work was done on A because the wall did not move.
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